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V. WITTE.

SEWING MACHINE.

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SEWING MACHINE.

Patented Oct. 13, 1896.

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SEWING MACHINE.

No. 569,441. Patented Oct. 13, 1896.

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SEWING MACHINE.

N0. 569,441. Patented Oct. 13, 1896.

UNITED STATES PATENT OFFICE.'

VICTOR IVITTE, OF LONDON, ENGLAND.

SEWING-MACHINE.

SPECIFICATION forming part of Letters Patent No. 569,441, dated October13, 1896.

Application filed July 28, 1893. Serial No. 481,703. (No model.)Patented in England February 28, 1893, No. 4.353.

T0 @ZZ whom t may concern,.-

Be it known that I, VICTOR XVITTE, a subject of the German Emperor,residing at t Newgate Street, in the city of London, England, haveinvented certain new and useful Sewing Mechanism for Forming a Lock,Chain, or Locked-Chain Stitch, (for which a patent has been granted tome in Great Britain, No. 4,358, dated February 28, 1893,) of which thefollowing is a specication.

This invention refers to loop-formin g mechanism of sewing-machineshaving verticallyreciprocating needles and a rotating shaft carrying ahook, the latter being recessed centrally to carry a removable bobbincontaining an under or second thread to form a lock-stitch. In suchmachines, where it is desired to form a chain or locked-chain stitch, alooping device has been employed which receives the loop of thread fromthe rotating hook, retains and holds the same, and presents the loop tothe needle on its next descent in order to form the chain.

My present invention relates to the construction of the particular loopretaining and spreading device and its combination with the describedmechanism for carrying and operating the same and for throwing the saidlooping device out of action when it is required to form an ordinarylock-stitch.

Suitable means, such as I have described and shown only by way ofexample, are provided, whereby the bobbin-case may be removed orreplaced and held within the hollow of the rotating hook.

The feed mechanism described and shown herein is to more clearlyillustrate the operation of the whole machine, but such feedingmechanism, being a separate invention, has been patented to me in theUnited States under date of March 5, 1895, No. 535,181.

In the drawings, Figure 1 is an elevation and partial section of themachine. Fig. 2 is an inverted plan showing the mechanism beneath thebase-plate of the machine. Fig. 3 is an end elevation and section of thebaseplate. Figs. 4 and 5 are respectively a central vertical section anda plan view of the throat-plate. Fig. 6 is a perspective view of aportion of a loop-spreading device. Fig. 7

is a vertical section showing the looper, with the bobbin-case, inposition on a larger scale than Figs. 1 and 2. Figs. 8, 9, 10, and 11are diagrams illustrating the operation of the stitch mechanism. Fig. 12illustrates the lock-chain stitch as it appears upon the under part ofthe material, and Fig. 13 shows the same stitch upon the upper part ofthe material.

Similar letters of reference indicate like parts in the several figures.

A is the base-plate of the machine.

B is the arm carrying the head-framing C.

D is the main driving-shaft.

E is the needle-bar receiving reciprocative motion from the main shaft Dat proper tim es.

F is an ordinary thread-tension, and G is a thread-take-up arm. i

H is the presser-foot, raised or lowered by finger-level' I-I.

J, Figs. 1 and 2, is the lever for communieating rotary motion from themain shaft D to the looper-shaft J.

I have not inthe drawings considered it necessary to illustrateparticularly the modes of communicating motion from the maindriving-shaft to the needle-bar E, the threadtake-up arm G, andlooper-shaft J as such mechanism is well known to those skilled in theart and doos not form any part of my invention.

The needle-thread passes from the spool B over a thread-guide F betweenthe tensionplates F, down to the thread-guide F2, up through the eye ofthe thread take-up G, through a thread-clamp G, and through theneedle-eye. Upon the end of the looper-shaft J below the needle, isfixed the rotarylooper J 2, having a hook J 3, and recessed centrally toreceive a bobbin-case J 4, Fig. 7, containing the under-thread spool.

According to my invention I tix a radiusarm N, pivoted at N, seas to becapable of horizontal motion, to the under side of the base-plate A,Fig. 2, this arm N being pressed in the direction of the arrow, Fig. 2,by a spring N2. N:3 is a bracket on arm N, which bracket, when the armis in action, comes against a cani ITT, iixed on the rotatingloopershaft J', the rotation of the cam N' serving to give the arm 1Icertain motions, as mentioned hereinafter when describing the action ofthe stitch devices. Near the end of the arm N and projecting laterallytherefrom are IOC two fingers N4 N 5, N4 being fixed to the arm N andNpivoted thereto and held by a spring N6, Fig. 2, in contact with thefinger N4. These fingers N4 N5, when in contact with each other, form anearly cylindrical bar, as at Fig. 6, throughout the greater part oftheir length, but are, nearly at their extremities, bent apart from oneanother and again closed together so that their extremities are again incontact, as shown at Fig. 6. It is through this bowed space between thefingers N4 ND that the needle passes in its descent through the loop ofthread carried by the spreader, and upon the retrograde mot-ion of thelatter the finger N5 turns on its pivot and allows the needle to passaway from the bowed part.

The bobbin-case may conveniently be held within the looper-disk, so asto be capable of removal when required by a ring K, carried by arm K onshaft K2, sliding in bearings KS on the under side of the base-plate A.The shaft K2 is retained in position by a spring K4, Fig. 2. WVhen it isdesired to remove or replace the shuttle-spool case, the knob K5 isseized by the operator and pulled, the spring compressed, and the shaftK2 partially rotated, bringing the ring K into the position shown inFig. 3, when the spool-case J4, Fig. 7, may be removed or placed inposition as required. K6 is a pin fixed ontovthe arm K of the ring K,and this pin KG takes into an aperture in the extension of one of theiixed bearings K3 when the ring is placed as in Figs. l and 2, andthereby insures accuracy of position. The shuttle-spool case J4 has afixed tongue J4X, which takes into the recess KX, Fig. 2, of the ring Kwhen the latter is closed upon it, whereby the said shuttie-spool caseis prevented from being rotated. The throat plate, Figs. et and 5, isformed with the needle-aperture and is slotted to receive the bifurcatedfeed-jaw, as is common in such sewing-machines. Located beneath thethroat-plate and attached thereto is a loop-guard R, consisting of apiece of wire extending transversely to the aperture in the throat-plateand serving to prevent the loops of needle-thread drifting toward theleft hand of the stitch devices and out of the zone of their action.

The feed is actuated by two cams ,7'5 jG on the looper-shaft acting uponan arm L, upon which the feed-dog L' is fixed. The feedarm L is pivotedat its rear end between two arms of a rock-shaft L3, carried in centerbearings from lugs on the under side of the base-plate. Beneath thebase-plate, Fig. 2, is provided a sliding bar M with a tapered end tocoact with a part L6 on the arm of the rocking shaft L3. By advancingthe bar M toward the left hand in Fig. 2 the distance which thefeed-lever will be returned by the spring L5 will be limited, andconsequently a s horter stitch will be produced, and by moving the bar Mto the right hand, Fig. 2, a longer stitch is produced. Motion iscommunicated to the bar M through the rackteeth thereon gearing with apinion M', Fig. 2, operated by an ordinary knob upon the stem of thepinion, said knob being provided with means for effecting the desiredlength of stitch. The thread take-up arm, as is usual, is timed to risefrom the full-line position, Fig. l, to the dotted position therein atthe commencement of the downward movement of the needle and draws threadfrom the needle-spool, the take-up G becoming again partially loweredbefore the needle has finished its descent.

I provide a thread-clamp device, (shown at Figs. l and 3,) to which Ishall refer, although I do not lay claim to special novelty therein. Apiece of spring metal is fixed to the machine-head, the thread passingfrom the eye of the take-up arm G over a fixed guide-arm C2 on the frameand then between a finger T2 and the lower part of the machine-head C'.The lower part of the spring-piece is formed with a bearing-piece T3,and there is a recess of suitable length formed in the bar E, so thatwhen the recess comes opposite the bearing-piece T3 the finger T2presses the thread between itself and the frame-head C' and produces atemporary stop upon the thread-supply.

The operation of the machine, when it is desired to produce alocked-chain stitch such as is shown at diagrams E and F, hereinbeforereferred to, is as follows: The piece of work is placed in position, thepresser-foot H lowered, the bobbin-case J 4 is inserted into the hollowof the rotating hook-disk J2 and retained therein by allowing theguard-ring K to close upon the same, the tongue of the bobbin-casepreventing its rotation. The operating-lever P is now placed into thedotted position shown at Fig. 2, thereby allowing the movements of thespreader to be controlled by its cam N7. Upon the machine being operatedthe needle descends through the material and through the closed eye ofthe spreader, as in diagrams Figs. 8 and 6, and then sheds its loop ofneedle-thread, the take-up lever G descending from its upper dottedposition in Fig. l. The loop of needle-thread is caught by the rotatinghook-J3. In the diagram Fig. 8 the hook is just about to catch a loop,and just as it has caught the loop and the needle commences to rise thespreader recedes to the right hand, Fig. 1l, its articulated ngeropening by contact with the needle, it immediately closing again by theaction of the separate spring N, and the fingers thus pass away from theneedle while the latter completes its rise, and the fingers N4 N5rapidly advance to the left hand to the position shown in diagram Fig.9, the said fingers passing through the loop, while the hook J3 carriesthe said loop of thread around the bobbin-case, casts it o, (as it isabout to do at Fig. 9,) and the feed having now taken place the take-upbrings the loop of thread up onto the fingers, Fig. 10. The fingersthenY move from position in Fig. 9 to IOO IIO

Fig. 8, and the needle having risen comes down again through the iingerseye, passes through the loop, (carried around the iin gers, as at Fig.S, and the latter immediately receding the articulated finger opens, asbefore, to allow the instrument to pass away from the needle andimmediately closing again by the spring N6. The hook then takes a freshloop from the needle, and while doing this (taking the loop) thethread-clamp device arrests and holds the thread, and consequentlythe'hook in the course of its rotation draws up or tightens thepreviouslycaught loop. Thusthe locking-thread contained in the bobbin isdeposited within the loops formed by the chain-stitch and a stitch isproduced as is shown in diagrams Figs. 12

and I3.

To produce the ordinary chain-stitch, all that is necessary is to removethe bobbin-case J 4, which may be readily done by releasing it from itsguard ring K, as previously explained. XVhen the chain stitch is beingproduced, the spreader carrying-arm N is left in action.

To produce the ordinary lock-stitch, the shuttle spool and case areplaced in position, Fig. 7, and the spreader-arm N is thrown out ofaction by moving the finger-lever Pinto the position shown by full linesin Fig. 2.

I am aware that in forming a chain-stitch it is not new to employ apointed bar or an open-forked instrument with rigid prongs, and I amaware that such a forked instrument has been made of spring metal tocause the prongs to be normally closed.

I am also aware that thumb-and-inger77 devices composed of two jointedparts have been employed to seize a thread between them and to aid inpassing it around a bobbin-case, and similar contrivances have beenemployed a's thread-laying instruments.

I am aware that it is not new to employ a looper having two fingers eachhinged, actuated by tappets and carried by a sliding plate, such looperacting in conjunction with a gripper and as described in Dimocks UnitedStates Patent No. 20,413.

I am also aware that it is not new to elnploy an arm pivoted at one endand carrying a looping instrument at the other end. Neither is it new toemploy in combination with a slide a forked plate to act as a loopretainer and spreader, as described in Kohlers United States Patent No.466,906; but I am not aware that the combination of aparticularly-constructed looper composed of one fixed and onespring-hinged nger mounted and acting in conjunction with the parts described has before been produced and as hereinafter claimed.

I claim as my invention- In loop-forming mechanism for sewingmachines,the combination with a rotating shaft, a hook carried thereby andadapted to receive a centrally-located detachable -bobbin-case and avertically-reciprocating needle, of a horizontal swinging arm N pivotedat one end beneath the base-plate and a bracket N3 on the arm N, a camN7 on the rotating shaft of the hook to give motion to the bracket N3and arm N, and a spring N2 for moving the arm N toward the cam N7, a1inger N4 rigidly fixed to and projecting laterally from the free end ofarm N and an adjacent finger N 5 pivoted to the arm N, a spring N6 tohold the linger N5 in contact with the finger N4, the fingers being bentin opposite directions near their extremities to form an eye with theextremities meeting for the passage of the needle and the fingerstogether forming a cylindrical neck rearward oi. the eye, and a lever Ppvoted on the base-plate to throw the arm N and its fingers N4, N5 outof the region of the cam action when required, substantially as setforth.

Signed by me this 3d day of July, 1893.

VICTOR WITTE. lVitnesses E. G. BREWER, E. ECAILLE.

